[1019] NOTE ON THE CRYSTALLIZATION 

 OF SODIUM IODIDE FROM ALCOHOLS 1 



AN accidental observation during the preparation of some 

 ethers by Williamson's method led to the experiments de- 

 tailed below, which are [1020] merely presented as an addi- 

 tion to the somewhat restricted literature upon the addition 

 products between haloid salts and alcohols. 



Sodium iodide is very soluble in absolute methyl alcohol 

 and is not precipitated therefrom upon the addition of a con- 

 siderable volume of absolute ether, while wet ether produces 

 immediate separation. On cooling a warm solution, rather 

 large plate-shaped crystals separate out, while a solution 

 saturated at room temperature and then cooled below 

 becomes thoroughly permeated with brilliant white felted 

 needles; although differing markedly in appearance, these 

 two kinds of crystals are identical in composition. 



The iodine was determined by Volhard's method; the 

 methyl alcohol, by heating in a current of air and absorbing 

 the vapors in sulphuric acid; the gain in the weight of the 

 latter corresponding accurately to the loss experienced by the 

 crystals. The results agreed very closely with the formula 

 NaI.3CH 4 O, 38.91 and 38.55 per cent of methyl alcohol 

 and 51.50 per cent of iodine (calculated for NaI.3CH 4 O, 

 39.06 and 51.58 per cent). 



Potassium iodide, while fairly soluble in alcohol, crystal- 

 lizes free from it, and this seems to be quite a characteristic 

 distinction between the two salts. Sodium iodide crystallizes 

 from ethyl alcohol, forming an addition product, although not 



1 Reprinted from Journal of the American Chemical Society, 27, 1019 (1905). 



